It is dangerous to fall asleep at the wheel. Techniques to detect such a state are known. Japanese Unexamined Patent Application Publication No. 2011-128966A discloses a device that obtains feature points from a captured image of a driver's face and determines the sleepiness of the driver. Japanese Unexamined Patent Application Publication No. 2009-223752A discloses a device that calculates a degree of risk from the eye opening time and eye closing time of a driver and gives an alarm to the driver when the degree exceeds a threshold.